@misc{RueckBierlLechneretal., author = {R{\"u}ck, Thomas and Bierl, Rudolf and Lechner, Alfred and Graf, Antonia and Dams, Florian and Schreiner, Rupert and Auchter, Eberhard and Kriz, Willy and Deubzer, MIchael and Schiller, Frank and Mottok, J{\"u}rgen and Niemetz, Michael and Margull, Ulrich and Hagel, Georg and Utesch, Matthias and Waldherr, Franz and B{\"o}hm, Matthias and Fraunhoffer, Judith and Gardeia, Armin and Schneider, Ralph and Streubel, Janet and Landes, Dieter and Studt, Reimer and Peuker, Dominik and Scharfenberg, Georg and Hook, Christian and Schuster, Dietwald and Ehrlich, Ingo and Dinnebier, Heinrich and Briem, Ulrich and L{\"a}mmlein, Stephan and Koder, Alexander and Bialek, Adam and Genewsky, Axel and Neumeier, Michael and Schlosser, Philipp and Rabl, Hans-Peter and Paule, Matthias and Galster, Christoph and Schiedermeier, Michael and Zwickel, Andreas and Hobmeier, Christoph and Bischoff, Tobias and Rill, Georg and Schaeffer, Thomas and Arbesmeier, Martin and Groß, Andreas and Schlegl, Thomas and Becker, Mark and Senn, Konrad and Schliekmann, Claus and Scholz, Peter and Sippl, Christian and Grill, Martin}, title = {Forschungsbericht 2011 / Hochschule f{\"u}r Angewandte Wissenschaften - Fachhochschule Regensburg}, editor = {Eckstein, Josef}, address = {Regensburg}, organization = {Hochschule f{\"u}r Angewandte Wissenschaften Regensburg}, issn = {1868-3533}, doi = {10.35096/othr/pub-732}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-7321}, language = {de} } @article{SchaefferHerrmannSchratzenstalleretal., author = {Schaeffer, Leon and Herrmann, David and Schratzenstaller, Thomas and Dendorfer, Sebastian and B{\"o}hm, Valter}, title = {Preliminary theoretical considerations on the stiffness characteristics of a tensegrity joint for the use in dynamic orthoses}, series = {Journal of Medical Robotics Research}, journal = {Journal of Medical Robotics Research}, publisher = {World Scientific}, doi = {10.1142/S2424905X23400081}, abstract = {Early motion therapy plays an important role for effective long-term healing of joint injuries. In many cases, conventional dynamic orthoses fail to address the intricate movement possibilities of the underlying joints, limited by their simplistic joint representations, often represented by revolute joints, enabling rotations by only one axis. In this paper, a two-dimensional compliant tensegrity joint for use in biomedical applications is investigated. It consists of two compressed members and five compliant tensioned members. Relative movement possibilities are realized by the intrinsic compliance of the structure. In the development of these systems, the first step is the determination of the static stable equilibrium. This analysis is conducted in this paper by considering the potential energy approach or by using the geometric nonlinear finite element method. The mechanical behavior of the structure is assessed with a specific emphasis on its mechanical compliance. The primary objective of this study is the investigation of the influence of structural parameters on the overall stiffness and movability of the structure. The results underscore the significant effect of member parameters on the stiffness and movability of the compliant tensegrity joint, particularly under varying load magnitudes. These findings provide insights for optimizing the joint's performance, contributing to its potential application in advanced orthotic and exoskeleton devices.}, language = {en} } @inproceedings{SchulzVoglGeigeretal., author = {Schulz, Carsten and Vogl, Yannick and Geiger, Benjamin and Schaeffer, Thomas}, title = {Lumped-Mass-Modellierung von F{\"o}rderb{\"a}ndern am Beispiel eines Zwei-Walzensystems mit flexiblen Walzen}, series = {Dresdner Maschinenelemente Kolloquium - DMK 2024, 14.-15. Mai 2024, Dresden}, booktitle = {Dresdner Maschinenelemente Kolloquium - DMK 2024, 14.-15. Mai 2024, Dresden}, language = {de} } @article{RillSchaefferSchuderer, author = {Rill, Georg and Schaeffer, Thomas and Schuderer, Matthias}, title = {LuGre or not LuGre}, series = {Multibody System Dynamics}, journal = {Multibody System Dynamics}, publisher = {Springer}, doi = {10.1007/s11044-023-09909-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-65653}, pages = {28}, abstract = {The LuGre model is widely used in the analysis and control of systems with friction. Recently, it has even been made available in the commercial multibody dynamics simulation software system Adams. However, the LuGre model exhibits well-known drawbacks like too low and force rate-dependent break-away forces, drift problems during sticking periods, and significant differences in non-stationary situations between the pre-defined friction law and the one produced by the LuGre model. In the present literature, these problems are supposed to come from the model dynamics or its nonlinear nature. However, most of these drawbacks are not simple side effects of a dynamic friction model but are caused in the LuGre approach, as shown here, by a too simple and inconsistent model of the bristle dynamics. Standard examples and a more practical application demonstrate that the LuGre model is not a "what you see is what you get" approach. A dynamic friction model with accurate bristle dynamics and consistent friction force is set up here. It provides insight into the physical basis of the LuGre model dynamics. However, it results in a nonlinear and implicit differential equation, whose solution will not be easy because of the ambiguity of the friction characteristics. The standard workaround, a static model based on simple regularized characteristics, produces reliable and generally satisfactory results but definitely cannot maintain a stick. The paper presents a second-order dynamic friction model, which may serve as an alternative. It can maintain a stick and produces realistic and reliable results.}, language = {en} } @article{SchudererRillSchaefferetal., author = {Schuderer, Matthias and Rill, Georg and Schaeffer, Thomas and Schulz, Carsten}, title = {Friction modeling from a practical point of view}, series = {Multibody System Dynamics}, journal = {Multibody System Dynamics}, publisher = {Springernature}, issn = {1384-5640}, doi = {10.1007/s11044-024-09978-0}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-72513}, pages = {18}, abstract = {AbstractRegularized static friction models have been used successfully for many years. However, they are unable to maintain static friction in detail. For this reason, dynamic friction models have been developed and published in the literature. However, commercial multibody simulation packages such as Adams, RecurDyn, and Simpack have developed their own specific stick-slip models instead of adopting one of the public domain approaches. This article introduces the fundamentals of these commercial models and their behavior from a practical point of view. The stick-slip models were applied to a simple test model and a more sophisticated model of a festoon cable system using their standard parameters.}, language = {en} } @article{SchulzVoglGeigeretal., author = {Schulz, Carsten and Vogl, Yannick and Geiger, Benjamin and Schaeffer, Thomas}, title = {Pros and cons of Lumped Mass Modelling of conveyor belts using a two-roller system}, series = {Forschung im Ingenieurwesen}, volume = {88}, journal = {Forschung im Ingenieurwesen}, number = {1}, publisher = {Springer Nature}, issn = {0015-7899}, doi = {10.1007/s10010-024-00736-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-72891}, pages = {9}, abstract = {Im Betrieb von F{\"o}rderb{\"a}ndern auftretende Ph{\"a}nomene sind das Bandwandern in Achsrichtung der Walzen und die Bandverformung in der Bandebene [1, S. 142]. Das Bandwandern ist bisher detailliert untersucht [2-4], w{\"a}hrend die Bandverformung Gegenstand weniger Ver{\"o}ffentlichungen ist. Deshalb wird in diesem Artikel eine Methode zur Berechnung der sich im dynamischen Betrieb einstellenden Verformung eines elastischen F{\"o}rderbandes vorgestellt. Dazu wird ein Mehrk{\"o}rpersimulations-Modell basierend auf der Lumped-Mass-Modellierung verwendet. Als Untersuchungsbeispiel dient ein Zwei-Walzensystem mit flexiblen und zylindrischen Walzen, sowie ein flexibles F{\"o}rderband. Es zeigt sich, dass mit der Lumped-Mass-Modellierung eine dynamische Bandverformung, die von der gew{\"a}hlten Diskretisierung abh{\"a}ngt, berechnet werden kann. Aufgrund dieser Abh{\"a}ngigkeit ist es notwendig eine Konvergenzanalyse durchzuf{\"u}hren. Zus{\"a}tzlich ist darauf zu achten, dass die k{\"u}nstliche Anregung aufgrund der Lumped-Mass-Modellierung nicht mit einer Eigenfrequenz des Modells zusammenf{\"a}llt.}, language = {en} } @book{RillSchaeffer, author = {Rill, Georg and Schaeffer, Thomas}, title = {Grundlagen und Methodik der Mehrk{\"o}rpersimulation : Vertieft in Matlab-Beispielen, {\"U}bungen und Anwendungen}, publisher = {Springer}, address = {Berlin}, doi = {10.1007/978-3-658-06084-8}, pages = {215}, abstract = {Dieses Lehrbuch vermittelt nicht nur Grundlagen, sondern stellt auch die Methoden der Mehrk{\"o}rpersimulation anschaulich dar und erl{\"a}utert an einfachen Beispielen die Vor- und Nachteile bei der praktischen Anwendung. In den Text integrierte Matlab-Skripte und -Funktionen verdeutlichen die einzelnen Methoden und erm{\"o}glichen es, Aufwand und Problematik bei der Umsetzung der Theorie innerhalb von Simulationsprogrammen einzusch{\"a}tzen. Die Modellbildung, die mathematische Beschreibung und die numerische Simulation von Systemen starrer K{\"o}rper bilden dabei die Schwerpunkte. Konkret behandelte Beispiele sind die Eigendynamik eines Traktors mit gefederter Vorderachse, das Rotorblatt eines Hubschraubers sowie die Vorderachse eines Pkws. Die entsprechenden Matlab-Skripte und L{\"o}sungen zu den {\"U}bungsaufgaben k{\"o}nnen auf der Springer-Homepage beim Buch heruntergeladen werden. Der Inhalt Dynamik des starren K{\"o}rpers - Bewegungsgleichungen - Starre K{\"o}rper mit elastischen und kinematischen Verbindungselementen - Integrationsverfahren - Rekursiver Algorithmus - Differential-Algebraische Gleichungen - Analyse von Mehrk{\"o}rpersystemen - Anwendungs- und {\"U}bungsbeispiele aus der Technik Die Zielgruppen Studenten des Maschinenbaus, der Elektrotechnik und Mechatronik sowie der Biomechanik an Hochschulen und Universit{\"a}ten Ingenieure in der Praxis, die sich mit Fragestellungen der Mehrk{\"o}rpersimulation (MKS) befassen Entwickler aus der Kfz-Technik sowie Fachleute aus F+E Die Autoren Dr.-Ing. Georg Rill ist Professor mit den Lehrgebieten Technische Mechanik, Ingenieurinformatik, Fahrdynamik, Mehrk{\"o}rperdynamik sowie Laborleiter Fahrdynamik. Dr.-Ing. Thomas Schaeffer ist Professor mit den Lehrgebieten Konstruktion, CAD, Maschinenelemente und Getriebetechnik, Mehrk{\"o}rpersysteme und Bewegungstechnik sowie Laborleiter Mehrk{\"o}rpersimulation, beide an der Ostbayerischen Technischen Hochschule (OTH) Regensburg.}, language = {de} } @book{RillSchaeffer, author = {Rill, Georg and Schaeffer, Thomas}, title = {Grundlagen und Methodik der Mehrk{\"o}rpersimulation}, edition = {3. Aufl.}, publisher = {Springer}, address = {Wiesbaden}, isbn = {978-3-658-16008-1}, doi = {10.1007/978-3-658-16009-8}, abstract = {Dieses Lehrbuch stellt die Methoden der Mehrk{\"o}rpersimulation anschaulich dar und erl{\"a}utert an einfachen Beispielen die Vor- und Nachteile bei der praktischen Anwendung. In den Text integrierte Matlab-Skripte und -Funktionen verdeutlichen die einzelnen Methoden. Die Modellbildung, die mathematische Beschreibung und die numerische Simulation von Systemen starrer K{\"o}rper bilden dabei die Schwerpunkte. Konkrete Beispiele beinhalten die Eigendynamik eines Traktors mit Vorderachsfederung, das Hubschrauberrotorblatt sowie eine Pkw- Vorderachse. Die entsprechenden Matlab-Skripte und L{\"o}sungen zu den {\"U}bungsaufgaben k{\"o}nnen auf der Springer-Homepage beim Buch heruntergeladen werden. Neu aufgenommen wurden SparseMatrix Operationen sowie ein Beispiel zu einfach geschlossenen kinematischen Schleifen.}, language = {de} } @misc{SchudererRillSchaefferetal., author = {Schuderer, Matthias and Rill, Georg and Schaeffer, Thomas and Schulz, Carsten}, title = {Friction modeling from a practical point of view}, series = {MULTIBODY2023: 11th ECCOMAS Thematic Conference on Multibody Dynamics, Tampa, 24th-28th May 2023}, journal = {MULTIBODY2023: 11th ECCOMAS Thematic Conference on Multibody Dynamics, Tampa, 24th-28th May 2023}, language = {en} } @unpublished{RillSchaefferSchuderer, author = {Rill, Georg and Schaeffer, Thomas and Schuderer, Matthias}, title = {LuGre or not LuGre}, doi = {10.21203/rs.3.rs-2266522/v1}, abstract = {The LuGre model is widely used in the analysis and control of systems with friction. Recently, it has even been made available in the commercial multibody dynamics simulation software system Adams. However, the LuGre model exhibits well-known drawbacks like, too low and force rate dependent break-away forces, drift problems during sticking periods, and significant differences in non-stationary situations between the pre-defined friction law and the one produced by the LuGre model. In the present literature, these problems are supposed to come from the model dynamics or its nonlinear nature. However, most of these drawbacks are not simple side effects of a dynamic friction model but are caused in the LuGre approach, as shown here, by a too simple and inconsistent model of the bristle dynamics. Standard examples and a more practical application demonstrate, that the LuGre model is not a "what you see is what you get" approach. A dynamic friction model with accurate bristle dynamics and consistent friction force is set up here. It provides insight into the physical basis of the LuGre model dynamics. However, it results in a nonlinear and implicit differential equation, whose solution will not be easy because of the ambiguity of the friction characteristics. The standard workaround, a static model based on a simple regularized characteristics, produces reliable and generally satisfactory results, but definitely cannot maintain stick. The paper presents a second order dynamic friction model, which may serve as an alternative. It can maintain stick and produces realistic and reliable results.}, language = {en} }